Apex & Fi
A Berlin-registered studio building private software for buying, renovating and reselling small flats in Paris. Two tools, one operator, no public product yet.
- Company
- Apex & Fi
- Legal form
- Sole proprietorship (Einzelunternehmen), Germany
- Registered
- June 2026, Finanzamt Berlin Mitte/Tiergarten
- Based in
- Berlin, Germany
- Founder
- Ugur Sakaoglu
- Contact
- Status
- Building — French operating company (SAS) planned for 2027
Deal OS
A private market memory for Paris residential listings. It collects listings from portals through an aggregator, keeps every value with its source, reconciles the same flat across sites, and records price cuts and relistings over time. Decisions — is this the same flat, do we pursue it — are made by a person and stored append-only; the software never writes its own score into the record. Rights per source (display, retention, deletion) are enforced in the database, with off-site backups and restore drills run live.
MdB Advisor
A sourced reference corpus on the French marchand de biens regime: tax, notary fees, deadlines and obligations, each claim tied to its primary source and confidence level. Built to answer the questions a first-time operator asks before signing.
How it is built
Specified and coded with Claude, reviewed blind by a second model, with every change shown failing before it is fixed. Two delivery slices are sealed with several thousand automated tests and machine-checked obligations.